Thanks!
@suffocation the string is 0.15 mm fishing line. I don't have a link because I didn't buy it online.
@Aleh The crane is a LTM 11200 in 1:50 scale produced by NZG: http://www.nzg.de/liebherr-ltm11200-9-5396.html

I spent the last two months in creating a climbing unit for this crane. Real tower cranes use climbing units to climb up along growing buildings during construction.
The climbing unit lifts the complete upper part of the crane, including the crane head and counter jib. A hydraulic cylinder mounted at the climbing cage braces itself on a “K” shaped strut of the tower and presses the upper part of the crane upwards. This happens 5 times until there is enough space beneath the slewing ring to insert the next tower section.
Here is an animation that shows the system developed by Liebherr:
The climbing unit was the most difficult feature of this model. At first, with the crane in its smallest configuration with 150 cm jib, it has to lift a weight of 4.2 kilograms. The finished climbing unit has a weight of 1.8 Kilograms, so the total load that has to be lifted (including one tower section in front of the climbing unit) is around 6.5 kilograms. This load is lifted by two linear actuators, extended by strings with a tear strength of 35 kilograms. Any other string I tested has torn. The two cylinders are powered by one XL-Motor using a worm gear with 1:24 reduction. But anyway the motor has to struggle with the weight.
Fortunately I found out the right dimensions of the climbing frame so that it guides the tower very well without too much friction or backlash, which is very important for the climbing process. This is because the climbing unit has to absorb all kinds of imbalance of the upper crane, which could not be adjusted by the counterweight or the position of the trolley and hook. So the climbing cage has to be very stable, too. Especially when the climbing process itself is done and the next tower section can be inserted. At this time, the climbing cage touches the tower at a length of only 15 cm. All upcoming forces have to be absorbed by this small part of the cage.
But this is enough of writing – after all there was the final load capacity test with a load of 4.8 kilograms (6.7 kilograms including the climbing unit). And what shall I say? It worked! Here is a picture of the climbing cage lifting this weight:
After adding some details such as walkways and a small trolley powered by 2 micro motors for inserting the tower sections, the climbing unit was finished:
The lifting unit:
Here is a video of the climbing process:
And a video of the crane climbing back down. In real life this happens when the construction of skyscrapers is completed and the crane can be disassembled:
At the moment I am improving the model and I am reducing some weight in the upper structure.
The jib lost 200 grams at a length of 200 cm:
All in all this is a very cool project for me and I like the result. I hope you like it, too - feel free to comment.

Hello everyone,
My current project is the construction of a Liebherr 250 EC-B towercrane in 1:18 scale. The model is fully functional. The hoist winch is powered by one XL-Motor, the trolley winch uses one M-Motor and the slewing ring is powered by two L-Motors. All motors are controlled by an S-Brick. I have started building this model 4 months ago.
Here the crane is assembled with 110 cm tower and 180 cm jib:
The maximum height under hook is about 2 meters; the maximum jib length is 230 cm. The total length of the model with 230 cm jib is 330 cm.
Here the crane is assembled with 150 cm tower and 230 cm jib:
The crane can be disassembled into the same number of small parts as the real crane. These parts have roughly the scale measurements.
Thanks to efferman´s turntable support ring the slewing ring is quite stable and rotates well (in the first video above the support ring was not attached yet, that is why the crane swings so much when it lifts or drops the load). The maximum capacity of the crane is approximately 400 grams in 2 fall-operation. But there is a second trolley and hook which allow an automatic change between 2 und 4 fall operation. The mechanism is the same as used for the real Liebherr fast erecting cranes und smaller EC-Bs.

Thanks.
@Blakbird I disassembled the model into modules and small parts. Fortunately everything fit into my VW Polo :D
The setup took ...maybe 4 hours. But adjusting everything and making the system work is another task and takes much longer. I only managed to get the one gondola mode to work at the exhibition. The fullauto mode did not work. But this is my personal aim for ABSolut Steinchen exhibition next year :)
The carrying ropes are made of cotton which is not the best choice at all. Maybe I will change them later. The pulling rope is a 2 mm Polypropylen rope which is quite perfect and works very well.
The carrying ropes are kept on tension by the baseplates which define the distance between the stations. The pulling rope is tensioned by a weight, like in some real 3s ropeways.
@Victor Imaginator there are levers at the gondola trolleys and rails in the stations. These open the clamps and release the pulling rope. You can see this in some of my videos on youtube.
I hope I was able to answer all of your questions. Otherwise: just ask :)

Hi, my last post was a long time ago, because i totally forgot to show you pictures and the video of the exhibition in june.
Efferman helped me during the disassembly:
The last four months i concentrated on other projects. But now I will continue with the 3s.
Last week i did some technical and optical changes and improvements. So I will try to make the ropeway more reliable during the next few weeks.
But first some pictures:
The gondolas are finished now, the problem was to get all the #3 connectors in red:
The walkways along the mast got a mesh floor.
And in the valley station the middle pulley was modified and strengthened.
The pulleys in front of the station were mdified in order to reduce the clearance to the sides. Because of this the pulling rope often jumped off the pulleys and the gondolas got stuck there. This is a mayor problem and i hope that this modification works well. The next test will show...
And another detail, the safety nets in front of the station were added:
That´s it for the moment. During the next weeks/ months I will continue testing and optimizing the system and also redesign the building of the mountain station in LDD in order to make it modular, buildable and more detailed. I suppose the partcount for the building will increase from 7000 to approximately 14000 bricks. But time will show...

A new video, I got the Zeta to run and it runs even smoother than the Lego gondolas:
[media]
[/media]But unfortunately the fully automatic operation with all gondolas does not work at the moment. Within every testdrive, there are new problems. The last 20 trys failed...but I will keep improving it untill it runs perfect again.

Thanks!
Here are some more details.
Signal lights on the turnstiles:
And a control panel, which is mounted in both stations in the original ropeway. It can be used to control all funtions individually:
It looks to massive I think, do you have ideas to improve it?
And an original "Zeta" gandola in scale 1:32. It can be connected to the Lego gondola drive, but it does not fit into the valley station unfortunately. It should look quite nice to see all 4 of them running in the system...

I spent the last days building the turnstile module. Yesterday the last sensors arrived, so I was able to assemble and programm everything. And after the first test I can say that the module works fine.
It contains 6 touch sensors, 3 micromotors and one RCX.
[media]
[/media]A friend send me leds for the position lights on top of the mast - that was a really cool surprise :)
I modified them a little to make them look more like the red balls on top of the original mast. Unfortunately 2 leds are connected to one cable, so I was not able to install the new parts there yet...
[media]
[/media]I also installed another motor to the conveyor system to get enough power for the two wheels between the curve and turnout. So totally there are 21 motors and 4 RCX in use now. When I tested the system after this modification the gondolas hit against the turnout and some gears broke, of course the ones just in the centre of the station... I really do not know why the gondolas blockade, I did not change anything in this area. I hope i can find and solve the mistake soon, but this seems to become difficult...
The old mechanics:
The two tires on the left are now powered by the lower m-motor:
I hope you like the news. I will try to fix the problem in the conveyor system as soon as possible.

I guess I forgot to show you pictures of the new foundation of the mountain station, so here they are.
at first the disassembly:
then I added about 200 technic beams and hundreds of pins to stabilize the 60 bottom plates:
The new, more original foundation. The front part includes spindels for the 4 carrying ropes and also the weight which keeps the right tenson on the pulling rope:
On the left the new weight, on the right the old one. Both have exactly the same weight.
The other part has some nice decals. I really like its proportions and overall look...just like the real thing.
I especially like this picture:

The steel construction between mast and mountain station is finished, including all the walkways.
Some impressions:
View from the station to the mast:
Walkways and working platform on top of the mast:
View from the mast to the mountain station:
The trafo for running the wheels went into the mountain:
A gondola passing by:
Next I will try running the ropeway with one gondola and adjust everything. But I am scared of testing it with all 4 gondolas more and more, I just do not believe that the programming still fits to the system...